Dark energy equation of state parameter and its evolution at low redshift

Tripathi, Ashutosh; Sangwan, Archana; Jassal, H. K.

doi:10.1088/1475-7516/2017/06/012

Cited by 77 publications

(58 citation statements)

References 77 publications

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“…Incidentally, such behaviours of the equation of state parameter, e.g., evolving Logarithmically, have already been addressed in [30,31] taking into account of Supernova Type Ia data [38,39], Baryon Acoustic Oscillation [40,41] and measurements of Hubble parameter [42,43]. It turns out that the numerical estimates of the best fit model obtained in [30,31] is consistent with the numerical results derived in the present analysis. Thus such behaviours of the equation of state parameter appear naturally in various interacting dark energy models as well, which are consistent with the current cosmological measurements.…”

supporting

confidence: 86%

“…1, the equation of state parameter changes with the redshift and hence is time dependent. It turns out that the above problem of time dependent equation of state parameter is equivalent to that of an interacting dark energy fluid, which has been extensively studied in [28][29][30][31][32][33][34][35][36][37]. Using Monte Carlo Markov Chain technique one can demonstrate that models involving interacting dark energy (or, time dependent equation of state parameter) has degeneracy between the matter density and the dark energy interaction rate.…”

mentioning

confidence: 99%

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Late-time acceleration driven by shift-symmetric Galileon in the presence of torsion

Banerjee

Chakraborty

Mukherjee³

2018

Phys. Rev. D

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A shift-symmetric Galileon model in presence of spacetime torsion has been constructed for the first time. This has been realized by localizing (or, gauging) the Galileon symmetry in flat spacetime in an appropriate manner. We have applied the above model to study the evolution of the universe at a cosmological scale. Interestingly, for a wide class of torsional structures we have shown that the model leads to late time cosmic acceleration. Furthermore, as torsion vanishes, our model reproduces the standard results.

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supporting

confidence: 86%

mentioning

confidence: 99%

Late-time acceleration driven by shift-symmetric Galileon in the presence of torsion

Banerjee

Chakraborty

Mukherjee³

2018

Phys. Rev. D

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“…This table shows the 3σ confidence limit for various data sets for the wCDM model, CPL parameterisation and logarithmic parameterisation. These constraints on parameters are as in [57].…”

Section: )mentioning

confidence: 99%

Reconstructing the dark energy potential

Sangwan

Mukherjee

Jassal

2018

J. Cosmol. Astropart. Phys.

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Abstract. Dark energy equation of state can be effectively described by that of a barotropic fluid. The barotropic fluid model describes the background evolution and the functional form of the equation of state parameter is well constrained by the observations. Equally viable explanations of dark energy are via scalar field models, both canonical and non-canonical; these scalar field models being low energy descriptions of an underlying high energy theory. In this paper, we attempt to reconcile the two approaches to dark energy by way of reconstructing the evolution of the scalar field potential. For this analysis, we consider canonical quintessence scalar field and the phantom field for this reconstruction. We attempt to understand the analytical or semi-analytical forms of scalar field potentials corresponding to typical well behaved parameterisations of dark energy using the constraints from recent observations.

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“…Many other parameterizations have been described in [11][12][13][14][15][16]. The parameters are then constrained using different datasets, a few examples of such work are [17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Low redshift observational constraints on tachyon models of dark energy

Singh

Sangwan

Jassal

2019

J. Cosmol. Astropart. Phys.

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The background evolution of an accelerated, dark energy dominated universe is aptly described by non-canonical tachyon scalar field models. The accelerated expansion of the universe is determined by the choice of a suitable scalar field potential; in the case of a tachyon field, a 'runaway' potential. In the absence of a fundamental theory, dark energy properties are studied in a phenomenological approach. This includes determining the model parameters using observations and to probe the allowed deviation from the cosmological constant model. In this paper, we present constraints on tachyon scalar field parameters from low redshift data for two different scalar field potentials. These scalar field potentials have been crucial in tachyon dark energy studies. The datasets considered in this paper include the supernova type Ia data, independent measurements of the Hubble parameter and the Baryon Acoustic Oscillation data. In this paper, we present constraints on tachyon field parameters using these observations and their combination. A combination of the datasets indicates that those model parameters are preferred which emulate the cosmological constant model. The initial value of the scalar field, in the unit of the Hubble constant, is bounded from below and does not require fine-tuning at larger values.

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Dark energy equation of state parameter and its evolution at low redshift

Cited by 77 publications

References 77 publications

Late-time acceleration driven by shift-symmetric Galileon in the presence of torsion

Late-time acceleration driven by shift-symmetric Galileon in the presence of torsion

Reconstructing the dark energy potential

Low redshift observational constraints on tachyon models of dark energy

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